IMHO, I want to know specifically what data is going thru' my application. If there are undef values, they should be handled. its all part of making a tight application.

It is also handy to specifically handle the undef cases as you may turn up bugs in your application, you didnt realise were there...

Update: you should _always_ be using your -T switch also and throwing away naughty chars (including but not limited to); ' " | when appropriate.